Measurement deviations indicate how much the measured value deviates from the actual value of the measurand
. There is the random measurement deviation and the systematic measurement deviationRandom measurement
deviations are indicatedby the fact that the measured values deviate from each other in several measurements
and vary unpredictably. Only when numerous measurements are performed can measurement deviations be eliminated by the calculated mean valueSystematic measurement deviations occur when deviations occur in an unlimited number of measurements of the same measurand under the same measurement conditions.
They may be errors in the measurement setup which can be corrected if the causes of the systematic error are known.